1. Field of the Invention
The present invention relates to method of and apparatus for measuring image alignment errors for image formation, by which test mark errors are more precisely measured using only two test marks, and more particularly, to method of and apparatus for checking an alignment of required test marks so that an image alignment of an image forming apparatus is corrected.
2. Description of the Related Art
In general, when an ink-jet image forming apparatus (for example, an ink-jet printer) performs a printing operation of an image, errors may occur in an image alignment. These errors cause a low printing quality due to a great variety of factors, such as non-uniformity of traveling of an ink-jet cartridge, a mechanical distortion, or a delay time of ink ejection. In the related art, a plurality of test marks are provided such that a user can check in advance the alignment state of images to correct errors.
FIGS. 1A and 1B show views in which a plurality of test marks for checking image alignment errors and correcting the image alignment errors are printed. In the related art, in order to correct errors in an image alignment, the test marks are printed. The test marks are divided into first test mark patterns for checking an alignment state on a horizontal axis as shown in FIG. 1A, and second test mark patterns for checking another alignment state on a vertical axis as shown in FIG. 1B. In general, several tens of the first or second test marks are provided to check the alignment state on the horizontal axis or the vertical axis. A user selects a test mark having a highest alignment state from the printed first or second test marks. Then, a correction operation is performed using an image forming apparatus in which the user selection is reflected. In first test mark patterns of FIG. 1A, the alignment state of a test mark 5 is the highest one of the first marks, and in second test mark patterns of FIG. 1B, the alignment state of a test mark 4 is the highest one of the second test marks. Thus, the user selects the test marks 4 and 5 such that a correction operation is properly performed.
However, in the related art, the user should check the first or second test marks to detect the alignment state of the test marks. Since this operation is performed with naked eyes of the user, it is time consuming, and the user easily gets tired. Also, improper test marks may be selected by the user.